Controllable Synthesis and Formation Mechanism Investigation of Prussian Blue Nanocrystals by Using the Polysaccharide Hydrolysis Method

Very controllable synthesis of cyanometallate-based coordination nanomaterials has been achieved by the hydrolysis reaction of polysaccharide (e.g., chitosan) in an acidic single precursor (i.e., potassium ferricyanide) solution. By controlling the hydrolysis rate of chitosan, Prussian blue (PB) nanoparticles and nanocubes with different sizes have been prepared via the rapid-seeding creation and long-time growth processes, respectively. The PB formation mechanism via the reducing effect of the hydrolysis product of chitosan and oxidation of the Prussian white intermediate in the solution was confirmed by Ultraviolet−visible (UV−vis), Fourier transform infrared (FT-IR), and transmission electron microscopy (TEM) measurements. The size- and structure-dependent magnetic property of PB was also investigated. The present approach allows simple and controllable preparation of transition metal hexacyanoferrate nanocrystals and is promising for the study of unique shape-, size-, and structure-dependent properties for optoelectronic, magnetic, and electrocatalytic applications.